The deal, which runs until 2013, is reward for taking the Robins from the League One basement to the Championship play-off final in three seasons.
Johnson said: “Crowds are up and we have made big strides so I’m sure the fans are behind me. The chairman is ambitious and I want to be part of it.”
City chairman Steve Lansdown said: “Gary has proved himself an excellent manager for us.”
contracts doesn't means a thing these days, if any, its probably just a bigger pie when sacked..